This invention relates to a lubricant control and more particularly to an improved lubricant control system and method for an internal combustion engine.
The lubrication of an internal combustion engine is particularly important, as should be readily apparent. However, the problems of providing adequate lubrication during the widely varying engine speeds and loads encountered during normal operation, particularly in automotive applications, is particularly difficult. This problem is particularly acute in conjunction with two cycle engines since the spent lubricant is discharged with the exhaust gases from the engine. Hence, if excess lubricant is employed, the exhaust emission problems can become acute and also particulates in the exhaust gases may become objectionable in the form of smoke. However, if inadequate lubrication is supplied, then disastrous results will occur.
It has, therefore, been proposed to eliminate the previously proposed method of lubricating two cycle engines by mixing lubricant with their fuel to provide positive lubricating systems that deliver lubricant directly to the engine for its lubrication. These systems may either inject lubricant into the intake passage or may deliver the lubricant directly to the components of the engine to be lubricated. Although these systems have particular advantages, they do present substantial problems.
Specifically, the amount of lubricant required for the engine per cycle varies substantially with load and speed and it is difficult to provide adequate and yet not excessive lubricant under all running conditions. In addition, although steady state conditions can be relatively easily satisfied, most engine applications do not afford any significant time of steady state running and accommodating transient conditions is quite difficult.
One form of lubricating system that has been provided introduces a fixed amount of lubricant at periodic time intervals. The amount of lubricant supplied is generally set larger as the engine load increases and the period between the supply intervals is set shorter as the engine speed increases. However, this type of system presents certain difficulties under certain types of running conditions such as high load, low speed operation. If this running condition is accommodated, then the satisfaction of the high load, high speed requirements is difficult to obtain.
One type of system has been proposed wherein the amount of lubricant supplied per cycle is fixed and the oil supply interval is varied in response to engine running conditions in the normal operating range. However, under high speed, high load conditions the oil supply interval is fixed and the amount of oil supplied per cycle is varied. Again, however, this type of system still has difficulty in accommodating transient conditions.
It is, therefore, a principal object to this invention to provide an improved lubricating system and method for an internal combustion engine.
It is a further object to this invention to provide an improved lubricating system and method for an engine, particularly of the two cycle type, that will accommodate all running conditions including transient conditions without introducing undesirable exhaust gas emissions or inadequate lubrication.
Most lubricating systems for engines also are designed so as to operate only when the engine is operating. These systems frequently employ pumps that are driven by the engine and hence when the engine is not running, no lubricant will be supplied. It is well known that a large amount of engine wear is the result of inadequate lubrication during the starting operation.
It is, therefore, a still further object to this invention to provide an improved lubricating system and method for an internal combustion engine wherein lubricant is supplied to the engine automatically before it is started.
With internal combustion engines there are a wide number of components that must be lubricated, even with two cycle engines. The lubricant requirement for the different elements of the engine do not vary in the same proportion, however, with respect to changed speed and load. Most lubricating systems proposed do accommodate variations in the amount of lubricant supplied to the components of the engine, but they cannot cope with the fact that the lubricant requirements for the various components do not vary in the same proportion in response to change in the engine running conditions.
It is, therefore, a still further object to this invention to provide an improved method and system for lubricating the various components of an engine which will insure that all components receive the proper amount of lubricant regardless of the running condition.
Many types of lubricating systems for engines operate by sensing engine running parameters and then varying the amount of lubricant supplied to the engine in response to the sensed parameters. Such devices can, as aforenoted, provide good lubrication and also good lubricant and emission control. However, the amount of lubricant required by the components of the engine varies not only in response to the engine running condition but also the time or life of the engine. For example, during initial break-in a greater amount of lubricant is required then once the engine has been broken in. However, conventional system do not accommodate these variations.
It is, therefore, a still further object to this invention to provide an improved lubricating system and method wherein the lubricant amount is varied not only in response to running conditions but also to the life of the engine.